The invention relates to electrostatic copying machines of the type provided with a flash discharge tube, used to illuminate an original to be copied, or used to fuse the toner image on the final copying medium, with the flash discharge tube being energized from a condensor battery which is to be accessible for servicing.
With electrostatic copying machines, it is becoming increasingly common to use a flash discharge tube both for the illumination of the original to be copied, and also for fusing the toner image on the final copying medium. In the former case, this makes it possible to expose a stationary original onto a moving copying medium without the use of travelling optical components, because the duration of the exposure is shorter than could give rise to loss of image sharpness on the transported copying medium. If the flash discharge lamp is used to fix a toner image, as described for example in German allowed patent application DT-AS No. 1,063,029, the energy needed to fuse the toner image can be applied in so short a time interval that the heat generated in the toner particles does not have time enough to be transmitted into the copying paper back of the toner image, to any appreciable degree. This type of selective fixing action saves on energy, and furthermore does less damage to the quality of the copying paper used. In both cases, to achieve the desired effect within the time available for the irradiation, a very considerable amount of energy must be utilized and stored in the flash condensors of the machine. These, for reasons of servicing convenience, are frequently arranged on a separate pull-out unit, removable as a whole from the copying machine. However, even after the machine has been disconnected from power, because of the amounts of energy which these condensors must store, a considerable danger of electrocution is presented to the service person who opens up the machine to gain access to its interior.